// 兼容
window.URL = window.URL || window.webkitURL
navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia
const HZRecorder = function (stream, config) {
  config = config || {}
  config.sampleBits = config.sampleBits || 8 // 采样数位 8, 16
  config.sampleRate = config.sampleRate || (44100 / 6) // 采样率(1/6 44100)
  const context = new (window.webkitAudioContext || window.AudioContext)()
  const audioInput = context.createMediaStreamSource(stream)
  const createScript = context.createScriptProcessor || context.createJavaScriptNode
  const recorder = createScript.apply(context, [4096, 1, 1])
  const audioData = {
    size: 0, // 录音文件长度
    buffer: [], // 录音缓存
    inputSampleRate: context.sampleRate, // 输入采样率
    inputSampleBits: 16, // 输入采样数位 8, 16
    outputSampleRate: config.sampleRate, // 输出采样率
    oututSampleBits: config.sampleBits, // 输出采样数位 8, 16
    input(data) {
      this.buffer.push(new Float32Array(data))
      this.size += data.length
    },
    compress() { // 合并压缩
      // 合并
      const data = new Float32Array(this.size)
      let offset = 0
      for (let i = 0; i < this.buffer.length; i++) {
        data.set(this.buffer[i], offset)
        offset += this.buffer[i].length
      }
      // 压缩
      const compression = Number.parseInt(this.inputSampleRate / this.outputSampleRate)
      const length = data.length / compression
      const result = new Float32Array(length)
      let index = 0; let j = 0
      while (index < length) {
        result[index] = data[j]
        j += compression
        index++
      }
      return result
    },
    encodeWAV() {
      const sampleRate = Math.min(this.inputSampleRate, this.outputSampleRate)
      const sampleBits = Math.min(this.inputSampleBits, this.oututSampleBits)
      const bytes = this.compress()
      const dataLength = bytes.length * (sampleBits / 8)
      const buffer = new ArrayBuffer(44 + dataLength)
      const data = new DataView(buffer)
      const channelCount = 1// 单声道
      let offset = 0
      const writeString = function (str) {
        for (let i = 0; i < str.length; i++) 
          data.setUint8(offset + i, str.charCodeAt(i))
                
      }
      // 资源交换文件标识符
      writeString('RIFF'); offset += 4
      // 下个地址开始到文件尾总字节数,即文件大小-8
      data.setUint32(offset, 36 + dataLength, true); offset += 4
      // WAV文件标志
      writeString('WAVE'); offset += 4
      // 波形格式标志
      writeString('fmt '); offset += 4
      // 过滤字节,一般为 0x10 = 16
      data.setUint32(offset, 16, true); offset += 4
      // 格式类别 (PCM形式采样数据)
      data.setUint16(offset, 1, true); offset += 2
      // 通道数
      data.setUint16(offset, channelCount, true); offset += 2
      // 采样率,每秒样本数,表示每个通道的播放速度
      data.setUint32(offset, sampleRate, true); offset += 4
      // 波形数据传输率 (每秒平均字节数) 单声道×每秒数据位数×每样本数据位/8
      data.setUint32(offset, channelCount * sampleRate * (sampleBits / 8), true); offset += 4
      // 快数据调整数 采样一次占用字节数 单声道×每样本的数据位数/8
      data.setUint16(offset, channelCount * (sampleBits / 8), true); offset += 2
      // 每样本数据位数
      data.setUint16(offset, sampleBits, true); offset += 2
      // 数据标识符
      writeString('data'); offset += 4
      // 采样数据总数,即数据总大小-44
      data.setUint32(offset, dataLength, true); offset += 4
      // 写入采样数据
      if (sampleBits === 8) {
        for (let i = 0; i < bytes.length; i++, offset++) {
          const s = Math.max(-1, Math.min(1, bytes[i]))
          let val = s < 0 ? s * 0x8000 : s * 0x7FFF
          val = Number.parseInt(255 / (65535 / (val + 32768)))
          data.setInt8(offset, val, true)
        }
      }
      else {
        for (let i = 0; i < bytes.length; i++, offset += 2) {
          const s = Math.max(-1, Math.min(1, bytes[i]))
          data.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7FFF, true)
        }
      }
      return new Blob([data], { type: 'audio/mp3' })
    },
  }
  // 开始录音
  this.start = function () {
    audioInput.connect(recorder)
    recorder.connect(context.destination)
  }
  // 停止
  this.stop = function () {
    recorder.disconnect()
  }
  // 获取音频文件
  this.getBlob = function () {
    this.stop()
    return audioData.encodeWAV()
  }
  // 回放
  this.play = function (audio) {
    const downRec = document.getElementById('downloadRec')
    downRec.href = window.URL.createObjectURL(this.getBlob())
    downRec.download = `${new Date().toLocaleString()  }.mp3`
    audio.src = window.URL.createObjectURL(this.getBlob())
  }
  // 上传
  this.upload = function (url, callback) {
    const fd = new FormData()
    fd.append('file', this.getBlob())
    const xhr = new XMLHttpRequest()
    /* eslint-disable */
        if (callback) {
            xhr.upload.addEventListener('progress', function (e) {
                callback('uploading', e)
            }, false)
            xhr.addEventListener('load', function (e) {
                callback('ok', e)
            }, false)
            xhr.addEventListener('error', function (e) {
                callback('error', e)
            }, false)
            xhr.addEventListener('abort', function (e) {
                callback('cancel', e)
            }, false)
        }
        /* eslint-disable */
        xhr.open('POST', url)
        xhr.send(fd)
    }
    // 音频采集
    recorder.onaudioprocess = function (e) {
        audioData.input(e.inputBuffer.getChannelData(0))
        // record(e.inputBuffer.getChannelData(0));
    }
}
// 抛出异常
HZRecorder.throwError = function (message) {
    alert(message)
    throw new function () { this.toString = function () { return message } }()
}
// 是否支持录音
HZRecorder.canRecording = (navigator.getUserMedia != null)
// 获取录音机
HZRecorder.get = function (callback, config) {
    if (callback) {
        if (navigator.getUserMedia) {
            navigator.getUserMedia(
                { audio: true } // 只启用音频
                , function (stream) {
                    let rec = new HZRecorder(stream, config)
                    callback(rec)
                }
                , function (error) {
                    switch (error.code || error.name) {
                        case 'PERMISSION_DENIED':
                        case 'PermissionDeniedError':
                            HZRecorder.throwError('用户拒绝提供信息。')
                            break
                        case 'NOT_SUPPORTED_ERROR':
                        case 'NotSupportedError':
                            HZRecorder.throwError('浏览器不支持硬件设备。')
                            break
                        case 'MANDATORY_UNSATISFIED_ERROR':
                        case 'MandatoryUnsatisfiedError':
                            HZRecorder.throwError('无法发现指定的硬件设备。')
                            break
                        default:
                            HZRecorder.throwError('无法打开麦克风。异常信息:' + (error.code || error.name))
                            break
                    }
                })
        } else {
            HZRecorder.throwErr('当前浏览器不支持录音功能。'); return
        }
    }
}
export default HZRecorder